Generally, in an alkaline battery, negative ions each having a negative charge are moved from a positive electrode thereof toward a negative electrode thereof and positive ions each having a positive charge are moved from the negative electrode toward the positive electrode, through an alkaline electrolyte solution thereof, and a separator is used between the positive and negative electrodes for separating these two electrodes from each other and for isolating a positive electrode active material and a negative electrode active material from each other. To this alkaline battery separator, various types of performance are required such as, for example,                preventing any internal short-circuiting between the positive electrode active material and the negative electrode active material,        retaining a high absorbent property for electrolyte solutions to generate a sufficient electrogenic reaction,        taking a less occupancy when the separator is incorporated into the battery to increase the amounts of the positive electrode active material and the negative electrode active material (for prolonging the usable time of the battery),        retaining the durability that prevents shrinkage and/or deterioration caused by an alkaline electrolyte solution and an alkaline depolarizes, and        preventing any buckling that is caused by vibrations generated during transportation or toting of the battery or by an impact generated by falling down of the battery, and any internal short-circuiting, after being incorporated in the battery.        
It has been proposed to use, in combination, alkali-resistant synthetic fibers and cellulose fibers obtained by precipitating cellulose directly from a solution that is obtained by dissolving cellulose in an organic solvent, to impart these types of performance to the separator. For example, Patent Document 1 discloses an alkaline battery separator that uses polyvinyl-based fibers and a fibrillated substance of solvent-spun cellulose fibers having a specific degree of beating, to improve its shielding property, its absorbent property for electrolyte solutions, and the like. Patent Document 2 discloses an alkaline battery separator that uses alkali-resistant synthetic fibers, and organic solvent-spun rayon fibers of purified cellulose fibers that have alkali resistance and that are capable being beaten, to prevent any internal short-circuiting and improve the alkali resistance, the denseness, the liquid retentivity, the electric property, and the like. Patent Document 3 discloses an alkali battery separator that uses alkali-resistant fibers, a fibrillated substance of organic solvent-spun cellulose fibers having a specific degree of beating, and mercerized natural pulp, to improve the impact resistance.